JP2021004277A - Aqueous dispersion of conductive carbon black raw material, manufacturing method of aqueous dispersion of conductive carbon black raw material, conductive carbon black powder, manufacturing method of conductive carbon black powder and manufacturing method of positive electrode for lithium ion secondary battery - Google Patents

Abstract

To provide an aqueous dispersion of a conductive carbon black raw material, which can simply and inexpensively manufacture a conductive material that can exhibit excellent conductivity with a reduced content ratio of a polyvalent metal ion.SOLUTION: An aqueous dispersion of a conductive carbon black material characterized by including oxidized carbon black having a nitrogen absorption specific surface area N2SA of 100 to 1500 m2/g, a value obtained by subtracting a statistical thickness specific surface area (STSA) from the nitrogen absorption specific surface area N2SA of 50 to 200 m2/g, a DBP oil absorption amount of 100 to 500 ml/100 g, an average particle size of 100 to 500 nm, a content concentration of a polyvalent metal of 10 to 100 mass ppm, and compressed electrical resistivity after heat treatment of 0.05 to 0.23 Ω cm.SELECTED DRAWING: None

Description

The present invention relates to an aqueous dispersion of a conductive carbon black raw material, a method for producing an aqueous dispersion of a conductive carbon black raw material, a method for producing a conductive carbon black powder, a method for producing a conductive carbon black powder, and a lithium ion secondary battery. It relates to a method for producing a positive electrode material.

In recent years, with the spread of mobile phones, notebook computers, and the like, lithium-ion secondary batteries have been attracting attention, and their demand is increasing year by year. In the current lithium ion secondary battery, in order to improve the efficiency of the battery reaction by increasing the electrode area, usually, a paint mixed with an electrode active material, a binder, a conductive material, etc. is applied on a strip-shaped metal foil. Both electrodes are used, and after being wound together with a separator, they are housed in a battery can (see Patent Document 1 (see JP-A-2003-308845).

Of these, a lithium transition metal composite oxide or the like is used as the electrode active material for the positive electrode. Since such an electrode active material alone has poor electron conductivity, that is, conductivity, carbon such as conductive carbon black whose structure is highly developed to impart conductivity and graphite whose crystals show remarkable anisotropy. A material is added as a conductive material and dispersed together with a binder (binding material) in a non-aqueous solvent such as N-methyl-2-pyrrolidone to prepare a slurry (see Patent Document 2 (Japanese Unexamined Patent Publication No. 2003-157846)). , This slurry is applied and dried on a metal foil to form a positive electrode.

By the way, the conductive material is required to have excellent conductivity and a small amount of metal impurities, particularly multivalent metal ions, which cause deterioration of battery performance. In the case of carbon black, it is known that the content and conductivity of metal impurities differ depending on the manufacturing method, but when used as a conductive material, it has excellent conductivity like other conductive materials. It is required that there are few metal impurities.

Japanese Unexamined Patent Publication No. 2003-308845 Japanese Unexamined Patent Publication No. 2003-157846

Therefore, it is conceivable to adopt acetylene black obtained by thermally decomposing acetylene gas as a conductive material, and to use a slurry of this acetylene black with a dispersant as a material for forming a positive electrode material for a lithium ion secondary battery.
Acetylene black has the advantages of higher conductivity and less metal impurities than furnace black obtained by incomplete combustion of hydrocarbon oil in a high-temperature gas.

However, acetylene black needs to be produced by the thermal decomposition of hydrocarbons or by the carbide method in which water is allowed to act on calcium carbide (carbide). Therefore, when this is used as a conductive material, acetylene black must be produced. There is a technical problem that it is difficult to manufacture an electrode material for a lithium ion secondary battery easily and inexpensively.

On the other hand, furnace black, which is generally used as carbon black, contains a large amount of metal impurities derived from raw material oil, and therefore, when it is used as a conductive material, it tends to cause deterioration of battery performance.

Therefore, the present invention is an aqueous dispersion of a conductive carbon black raw material capable of easily and inexpensively producing a conductive material capable of exhibiting excellent conductivity by reducing the content ratio of polyvalent metal ions, and the conductive carbon black raw material. It is an object of the present invention to provide a method for producing an aqueous dispersion, a method for producing a conductive carbon black powder, a method for producing a conductive carbon black powder, and a method for producing a positive electrode material for a lithium ion secondary battery.

In such a situation, as a result of diligent studies, the present inventor has a nitrogen adsorption specific surface area N ₂ SA of 100 to 1500 m ² / g, a value obtained by subtracting the statistical thickness specific surface area STSA from the nitrogen adsorption specific surface area N ₂ SA. 50 to 200 m ² / g, DBP oil absorption is 100 to 500 ml / 100 g, average particle size is 100 to 500 nm, polyvalent metal content concentration after heat treatment is 10 to 100 mass ppm, and compressed electricity. We have found that the above technical problems can be solved by an aqueous dispersion of a conductive carbon black raw material containing carbon oxide black having a specific resistance of 0.05 to 0.23 Ω · cm, and based on this finding, the present invention has been developed. It came to be completed.

That is, one embodiment of the present invention is
(1) Nitrogen adsorption specific surface area N ₂ SA is 100 to 1500 m ² / g,
The value obtained by subtracting the statistical thickness specific surface area STSA from the nitrogen adsorption specific surface area N ₂ SA is 50 to 200 m ² / g.
DBP oil absorption is 100-500ml / 100g,
The average particle size is 100-500 nm
The polyvalent metal content is 10 to 100 mass ppm,
An aqueous dispersion of a conductive carbon black raw material, which contains carbon oxide black having a compressed electrical resistivity of 0.05 to 0.23 Ω · cm after heat treatment.
(2) Nitrogen adsorption specific surface area N ₂ SA is 100 to 1500 m ² / g, nitrogen adsorption specific surface area N ₂ SA minus statistical thickness specific surface area STSA is 50 to 200 m ² / g, DBP oil absorption is 100. With respect to an aqueous slurry of carbon oxide black having an average particle size of 100 to 500 nm and having one or more anionic functional groups on the surface, up to ~ 500 ml / 100 g.
The alkali metal hydroxide is mixed and neutralized by heating in the presence of one or more selected from the water-soluble chelating agent or a salt thereof, or the alkali metal hydroxide is mixed and neutralized by heating and then the water-soluble chelating agent or its A neutralization step that mixes one or more selected from salts,
A method for producing an aqueous dispersion of a conductive carbon black raw material, which comprises performing a separation / removal step of separating and removing a polyvalent metal ion chelate complex from the mixed solution obtained in the neutralization step using a separation membrane.
(3) The aqueous dispersion of the conductive carbon black raw material according to (2) above, in which the alkali metal hydroxide is mixed with the aqueous slurry of carbon oxide black so as to have a pH of 6 to 12 in the neutralization step. Manufacturing method,
(4) The method for producing an aqueous dispersion of a conductive carbon black raw material according to (2) or (3) above, wherein the water-soluble chelating agent is an aminocarboxylic acid or a salt thereof.
(5) A type of carbon black oxide having one or more anionic functional groups on its surface is selected from a water-soluble chelating agent or a salt thereof under the conditions of pH 2 to pH 4 after oxidizing the carbon black by a liquid phase method. The method for producing an aqueous dispersion of a conductive carbon black raw material according to any one of (2) to (4) above, which is obtained by mixing with the above and then preliminarily separating polyvalent metal ions using a separation membrane.
(6) The aqueous dispersion of the conductive carbon black raw material according to any one of (2) to (5) above, wherein the separation membrane is an ultrafiltration membrane (UF), a reverse osmosis membrane (RO), or an electrodialysis membrane. Manufacturing method,
(7) Nitrogen adsorption specific surface area N ₂ SA is 100 to 1500 m ² / g,
The value obtained by subtracting the statistical thickness specific surface area STSA from the nitrogen adsorption specific surface area N ₂ SA is 50 to 200 m ² / g.
DBP oil absorption is 100-500ml / 100g,
The average particle size is 20-100 nm
Polyvalent metal content concentration is 10 to 100 mass ppm,
Compressed electrical resistivity is 0.05 to 0.23 Ω ・ cm
Conductive carbon black powder, characterized by being
(8) A method for producing a conductive carbon black powder, which comprises heat-treating the aqueous dispersion of the conductive carbon black raw material according to the above (1).
(9) Nitrogen adsorption specific surface area N ₂ SA is 100 to 1500 m ² / g, nitrogen adsorption specific surface area N ₂ SA minus statistical thickness specific surface area STSA is 50 to 200 m ² / g, DBP oil absorption is 100. With respect to an aqueous slurry of carbon oxide black having an average particle size of 100 to 500 nm and having one or more anionic functional groups on the surface, up to ~ 500 ml / 100 g.
The alkali metal hydroxide is mixed and neutralized by heating in the presence of one or more selected from the water-soluble chelating agent or a salt thereof, or the alkali metal hydroxide is mixed and neutralized by heating and then the water-soluble chelating agent or its A neutralization process that mixes one or more selected from salts,
An aqueous dispersion of a conductive carbon black raw material is prepared by performing a separation / removal step of separating and removing a polyvalent metal ion chelate complex from the mixed solution obtained in the neutralization step using a separation membrane, and then
A method for producing a conductive carbon black powder, which comprises performing a functional group removing step of heat-treating the obtained aqueous dispersion of the conductive carbon black raw material to remove the anionic functional group of the carbon oxide black.
(10) The method for producing a conductive carbon black powder according to (8) or (9) above, wherein the aqueous dispersion of the conductive carbon black raw material is heat-treated at 500 to 600 ° C.
(11) The aqueous dispersion of the conductive carbon black raw material according to (1) above, the aqueous dispersion of the conductive carbon black raw material obtained by the production method according to any one of (2) to (6) above. The conductive carbon black powder according to (7) above or the conductive carbon black powder obtained by the production method according to any one of (8) to (10) above.
Mix at least with electrode active material and binder,
It provides a method for manufacturing a positive electrode material for a lithium ion secondary battery, which is characterized by being applied to an electrode substrate and dried.

According to the present invention, an aqueous dispersion of a conductive carbon black raw material capable of easily and inexpensively producing a conductive material capable of exhibiting excellent conductivity with a reduced content ratio of polyvalent metal ions, such a conductive carbon black raw material A method for producing an aqueous dispersion, a method for producing a conductive carbon black powder, a method for producing a conductive carbon black powder, and a method for producing a positive electrode material for a lithium ion secondary battery can be provided.

<Aqueous dispersion of conductive carbon black raw material>
First, an aqueous dispersion of a conductive carbon black raw material according to the present invention will be described.
The aqueous dispersion of the conductive carbon black raw material according to the present invention is
Nitrogen adsorption specific surface area N ₂ SA is 100-1500 m ² / g,
The value obtained by subtracting the statistical thickness specific surface area STSA from the nitrogen adsorption specific surface area N ₂ SA is 50 to 200 m ² / g.
DBP oil absorption is 100-500ml / 100g,
The average particle size is 100-500 nm
The polyvalent metal content is 10 to 100 mass ppm,
It is characterized by containing carbon oxide black having a compression electrical resistivity of 0.05 to 0.23 Ω · cm after heat treatment.

The carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material according to the present invention has a nitrogen adsorption specific surface area N ₂ SA of 100 to 1500 m from the viewpoint of increasing the number of particles per unit weight to obtain conductivity. ^{It is 2} / g, preferably 100 to 500 m ² / g from the viewpoint of suppressing the increase in viscosity at the time of preparing the aqueous dispersion, and 200 from the viewpoint of achieving both the above-mentioned good conductivity and suppression of the increase in viscosity. More preferably, it is ~ 300 m ² / g.

In the aqueous dispersion of the conductive carbon black raw material according to the present invention, the nitrogen adsorption specific surface area N ₂ SA of the carbon oxide contained in the aqueous dispersion is within the above range, and this is obtained by heat treatment. The conductive carbon black produced is likely to have the same nitrogen adsorption specific surface area N ₂ SA, and the number of particles per unit weight is likely to be increased, so that the conductivity can be easily improved.

The nitrogen adsorption specific surface area N ₂ SA of carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material was JIS K 6217-2 using a fully automatic surface area measuring device (Gemini 2375 manufactured by Shimadzu Corporation). It means the value measured according to "Carbon black for rubber-Basic characteristics-Part 2, How to obtain specific surface area-Nitrogen adsorption method, Single point method" specified in.

The carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material according to the present invention has a nitrogen adsorption specific surface area from the viewpoint of increasing the number of particles per unit weight by having pores on the surface to obtain conductivity. N is from ₂ SA those minus the statistical thickness ratio surface area (STSA) is 50 to 200 m ² / g, a viscosity rise during aqueous dispersion preparation from the viewpoint of suppressing in 50 to 150 m ² / g Some are preferable, and 80 to 150 m ² / g is more preferable from the viewpoint of achieving both good conductivity and suppression of viscosity increase.

The statistical specific surface area of carbon oxide contained in the aqueous dispersion of the conductive carbon black raw material was determined by JIS K 6217-7 using a fully automatic surface area measuring device (Gemini 2375 manufactured by Shimadzu Corporation). Values measured according to the specified "Carbon Black for Rubber-Basic Properties-Part 7, Rubber Formulation-Multipoint Method Nitrogen Specific Surface Area (N ₂ SA) and Statistical Thickness Specific Surface Area (STSA)" means.

The carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material according to the present invention has a DBP (Dibutyl phthalate) oil absorption of 100 to 500 ml from the viewpoint of developing the structure structure of the carbon black and forming a conductive path. It is / 100 g, preferably 100 to 300 ml / 100 g from the viewpoint of suppressing the increase in viscosity during preparation of the aqueous dispersion, and 150 to 250 ml from the viewpoint of achieving both the formation of the conductive path and the suppression of the increase in viscosity. More preferably, it is / 100 g.

In the aqueous dispersion of the conductive carbon black raw material according to the present invention, when the DBP oil absorption amount of the carbon oxide black contained in the aqueous dispersion is within the above range, the conductive carbon obtained by heat-treating the aqueous dispersion is obtained. Black also tends to have the same DBP oil absorption amount, and a conductive path is easily formed, so that conductivity can be easily improved.

The DBP oil absorption amount of carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material is defined in JIS K 6217-4, "Carbon Black for Rubber-Basic Characteristics-Part 4, Obtaining DBP Absorption Amount". It means the value measured according to the method.

The carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material according to the present invention has an average particle size of 100 to 500 nm from the viewpoint of obtaining good dispersibility, and further improves the dispersibility. The temperature is preferably 150 to 400 nm, and more preferably 150 to 250 nm from the viewpoint of promoting the effect of removing impurity metals by the water-soluble chelating agent.

In the aqueous dispersion of the conductive carbon black raw material according to the present invention, when the average particle size of the carbon oxide black contained in the aqueous dispersion is within the above range, the conductive carbon obtained by heat-treating the aqueous dispersion is obtained. As for black, aggregates are reduced, the number of particles per unit weight can be easily increased, and conductivity can be easily improved.

The average particle size of carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material is 50% of the integrated particle size in the volume-based integrated particle size distribution measured by the laser diffraction type particle size distribution measuring device. It means the volume average particle size D50).
When the above carbon oxide black is prepared from furnace black as a raw material, the obtained carbon oxide black has the above nitrogen adsorption specific surface area N ₂ SA, statistical thickness specific surface area STSA, DBP oil absorption and average particle size. Therefore, according to the aqueous dispersion of the conductive carbon black raw material according to the present invention, conductive carbon black can be easily and inexpensively obtained by heat-treating the aqueous dispersion.

The amount of acidic hydroxyl groups of carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material according to the present invention is preferably 300 μmol / g to 1200 μmol / g from the viewpoint of sufficiently oxidizing and obtaining dispersibility, and is more uniform. It is more preferably 500 μmol / g to 1000 μmol / g from the viewpoint of obtaining a good dispersibility, and further preferably 800 μmol / g to 1000 μmol / g from the viewpoint of promoting the elution of metal impurities. Acidic hydroxyl group of the oxidized carbon black contained in the aqueous dispersion of the conductive carbon black feedstock according to the present invention, the carboxyl group of the oxidized carbon black (-COO ^-) weight and a hydroxyl group - meaning the sum of the amount ^(-O) To do. Considering the dispersibility of carbon oxide black in an aqueous medium, acidic hydroxyl groups are important as functional groups on the surface of carbon black particles, and carboxyl groups and hydroxyl groups play a particularly large role. Therefore, carbon oxide black The amount of acidic hydroxyl groups in the particles can be regarded as substantially the sum of the amount of carboxyl groups and the amount of hydroxyl groups.

The amount of acidic hydroxyl groups of carbon oxide black means a value measured by the following method.
(Sample preparation: acid cleaning and standard solution addition)
The obtained aqueous dispersion of carbon oxide black was dried at 110 ° C., 1.0 g of the powder crushed in a mortar or the like was collected in a centrifuge tube, 5.0 g of 0.5 mol / l hydrochloric acid was added, and several times. After shaking, solid-liquid separation is performed by a centrifuge. After performing this operation a total of 4 times, the solid matter is transferred to a 100 ml beaker and dried at 110 ° C. The dried solid is crushed in a mortar, 1.0 g of carbon oxide black is collected in an Erlenmeyer flask, 25 ml of 0.1 mol / l NaOH is added to the Erlenmeyer flask, and then the Erlenmeyer flask is placed in a shaker for 4 hours. Shake. Transfer the shaken liquid to a centrifuge tube and collect the supernatant liquid as a measurement sample.
(Measurement procedure: titration method and acid value calculation method)
The acid value is measured by potentiometric titration using an automatic titration device (809Titrando, manufactured by Metrohm). Prior to the measurement of the sample obtained above, 25 ml of 0.1 mol / l NaOH was titrated with 0.1 mol / l HCl as a blank, and the amount of HCl required for neutralization was measured. Titrate with 1 mol / l HCl and measure the amount of HCl required for neutralization. Substitute the obtained measured value into the following formula to obtain the acid value. The meanings of the symbols in the formula are shown below.
V _Blank [ml]: Titration amount of 0.1 mol / l NaOH required for neutralization when 25 ml of NaOH was titrated with 0.1 mol / l HCl V _Sample [ml]: Titration of 25 ml of sample with 0.1 mol / l HCl N _HCl [mol / l]: Concentration of HCl standard solution M _sample [g]: Weight of carbon oxide in the measurement sample Acid value [mmol / g] = (V _Blank − V _Sample ) × N _HCl / M _sample

In the aqueous dispersion of the conductive carbon black feedstock according to the present invention, for the -SO 3 _H group content and -PO ₄ H ₂ groups of the oxidized carbon black is not particularly limited.

The carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material according to the present invention has a polyvalent metal content of 10 to 100 from the viewpoint of suppressing metal elution into the system when used in the present application. It is mass ppm, preferably 10 to 80 mass ppm, and more preferably 10 to 50 mass ppm.

In the aqueous dispersion of the conductive carbon black raw material according to the present invention, the polyvalent metal content concentration of the carbon oxide contained in the aqueous dispersion after the heat treatment is within the above range, so that the aqueous dispersion can be obtained. The conductive carbon black obtained by heat treatment also has a similar polyvalent metal content concentration, and when used as a positive electrode material for a lithium secondary battery, deterioration of battery performance can be easily suppressed.

The polyvalent metal content concentration of carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material means a value measured by a method based on JIS K 0133. The content of each metal component is measured using an inductively coupled plasma emission spectroscopic analyzer (ICPS-7510, manufactured by Shimadzu Corporation). As the metal component, Mg, Al, Ca, Cr, Mn, Fe, Ni, Cu, Zn, and Pb are measured.

The carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material according to the present invention has a compression electrical resistivity of 0.05 to 0.23 Ω after heat treatment from the viewpoint of functioning as a conductive material in the positive electrode material. -Cm, more preferably 0.05 to 0.20 Ω · cm, and more preferably 0.05 to 0.10 Ω · cm from the viewpoint of obtaining conductivity even with a small amount of addition.

In the aqueous dispersion of the conductive carbon black raw material according to the present invention, the aqueous dispersion is heated when the compression electrical resistivity after the heat treatment of the carbon oxide contained in the aqueous dispersion is within the above range. The conductive carbon black obtained by the treatment also has the same compressive electrical resistivity, and when used as a positive electrode material for a lithium secondary battery, deterioration of battery performance can be easily suppressed.

The compressive resistivity of carbon oxide contained in the aqueous dispersion of the conductive carbon black raw material after the heat treatment means a value measured by a method based on JIS K 1469-2003. A load cell Ezgraph manufactured by Shimadzu Corporation was used as an apparatus.

The aqueous dispersion of the conductive carbon black raw material according to the present invention can be suitably produced by the method for producing the aqueous dispersion of the conductive carbon black raw material described below.

The acidic carbon black contained in the aqueous dispersion according to the present invention serves as a raw material for the conductive carbon black, and by separately removing the anionic functional group (acidic functional group) on the surface of the acidic carbon black, the conductivity having desired characteristics is obtained. You can get carbon black.

According to the present invention, it is possible to provide an aqueous dispersion of a conductive carbon black raw material capable of easily and inexpensively producing a conductive material capable of exhibiting excellent conductivity by reducing the content ratio of polyvalent metal ions.

<Manufacturing method of aqueous dispersion of conductive carbon black raw material>
Next, a method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention will be described.
The method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention is a method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention.
Nitrogen adsorption specific surface area N ₂ SA is 100 to 1500 m ² / g, and the value obtained by subtracting the statistical thickness specific surface area STSA from the nitrogen adsorption specific surface area N ₂ SA is 50 to 200 m ² / g.
For an aqueous slurry of carbon oxide having a DBP oil absorption of 100 to 500 ml / 100 g, an average particle size of 100 to 500 nm, and one or more anionic functional groups on the surface.
The alkali metal hydroxide is mixed and neutralized by heating in the presence of one or more selected from the water-soluble chelating agent or a salt thereof, or the alkali metal hydroxide is mixed and neutralized by heating and then the water-soluble chelating agent or its A neutralization step that mixes one or more selected from salts,
It is characterized in that a separation / removal step of separating and removing a multivalent metal ion chelate complex from the mixed solution obtained in the neutralization step is performed using a separation membrane.

In the production method of the aqueous dispersion of electrically conductive carbon black feedstock according to the present invention, as an aqueous slurry of oxidized carbon black, the nitrogen adsorption specific surface area _N 2 SA from 100~1500m ² / g, nitrogen adsorption specific surface area _N 2 SA The value obtained by subtracting the statistical thickness specific surface area STSA is 50 to 200 m ² / g, the DBP oil absorption is 100 to 500 ml / 100 g, the average particle size is 100 to 500 nm, and one or more anionic functional groups are formed on the surface. Use an aqueous slurry of carbon oxide having.

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, the carbon oxide black contained in the aqueous slurry has a nitrogen adsorption specific surface area N from the viewpoint of increasing the number of particles per unit weight to obtain conductivity. ₂ SA is, and those wherein 100~1500m ² / g, preferably has a 100 to 500 m ² / g from the viewpoint of suppressing increase in viscosity during aqueous dispersion preparation, the good conductivity and viscosity increase From the viewpoint of achieving both suppression, 200 to 300 m ² / g is more preferable.

The nitrogen adsorption specific surface area N ₂ SA of carbon oxide contained in the aqueous slurry is determined by using a fully automatic surface area measuring device (Gemini 2375 manufactured by Shimadzu Corporation) and defined in JIS K 6217-2. Carbon black for use-Basic characteristics-Part 2, How to obtain specific surface area-Nitrogen adsorption method, single point method "means the value measured.

The carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material according to the present invention has a nitrogen adsorption specific surface area from the viewpoint of increasing the number of particles per unit weight by having pores on the surface to obtain conductivity. N is from ₂ SA those minus the statistical thickness ratio surface area (STSA) is 50 to 200 m ² / g, a viscosity rise during aqueous dispersion preparation from the viewpoint of suppressing in 50 to 150 m ² / g Some are preferable, and those having a viscosity of 80 to 150 m ² / g are more preferable from the viewpoint of achieving both the above-mentioned good conductivity and suppression of viscosity increase.

The statistical specific surface area of carbon oxide contained in the aqueous dispersion of the conductive carbon black raw material was determined by JIS K 6217-7 using a fully automatic surface area measuring device (Gemini 2375 manufactured by Shimadzu Corporation). Values measured according to the specified "Carbon Black for Rubber-Basic Properties-Part 7, Rubber Formulation-Multipoint Method Nitrogen Specific Surface Area (N ₂ SA) and Statistical Thickness Specific Surface Area (STSA)" means.

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, the carbon oxide black contained in the aqueous slurry has a DBP (Dibutyl phthalate) from the viewpoint of developing the structure structure of the carbon black and forming a conductive path. ) The oil absorption amount is 100 to 500 ml / 100 g, preferably 100 to 300 ml / 100 g from the viewpoint of suppressing the increase in viscosity at the time of preparing the aqueous dispersion, and the formation of the conductive path and the suppression of the increase in viscosity are preferable. From the viewpoint of achieving both, 150 to 250 ml / 100 g is more preferable.

The DBP oil absorption amount of carbon oxide black contained in the aqueous slurry is a value measured according to "Carbon Black for Rubber-Basic Characteristics-Part 4, How to Obtain DBP Absorption Amount" specified in JIS K 6217-4. Means.

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, the carbon oxide black contained in the aqueous slurry has an average particle size of 100 to 500 nm from the viewpoint of obtaining good dispersibility. Further, it is preferably 150 to 400 nm from the viewpoint of further improving the dispersibility, and more preferably 150 to 250 nm from the viewpoint of promoting the effect of removing impurity metals by the water-soluble chelating agent.

The average particle size of carbon oxide black contained in the aqueous slurry is 50% of the integrated particle size in the volume-based integrated particle size distribution measured by a laser diffraction type particle size distribution measuring device (UPA150 manufactured by Microtrac Bell). It means the particle size (volume average particle size D50).

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, the nitrogen adsorption specific surface area N ₂ SA, DBP oil absorption amount and average particle size of carbon oxide contained in the aqueous slurry are each within the above ranges. As a result, the carbon oxide black obtained after the neutralization step and the separation / removal step described later can easily have the same nitrogen adsorption specific surface area N ₂ SA, statistical thickness specific surface area STSA, DBP oil absorption amount and average particle size. Become.

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, the carbon oxide black contained in the aqueous slurry can be easily prepared by introducing an anionic functional group into the carbon black.

Examples of the carbon black used as a raw material for the carbon oxide black include furnace black, and the carbon black may be acidic, neutral, or basic. When the carbon black is acidic, it may be used as it is as carbon oxide black, or it may be used as carbon oxide black after being further oxidized to a desired degree.

As the carbon black used as a raw material of carbon oxide black, it is preferable that the nitrogen adsorption specific surface area N ₂ SA is 100 to 1500 m ² / g from the viewpoint of increasing the number of particles per unit weight to obtain conductivity. It is more preferably 100 to 500 m ² / g from the viewpoint of suppressing the increase in viscosity during the preparation of the aqueous dispersion, and 200 to 300 m ² / g from the viewpoint of achieving both the above-mentioned good conductivity and suppression of the increase in viscosity. Is more preferable.
In addition, carbon black, which is a raw material of carbon oxide, has a statistical thickness from the nitrogen adsorption specific surface area N ₂ SA from the viewpoint of increasing the number of particles per unit weight to obtain conductivity by having pores on the surface. is are those specific surface area minus the (STSA) is 50 to 200 m ² / g, preferably has a 50 to 150 m ² / g viscosity rise during aqueous dispersion preparation from the viewpoint of suppressing, the better From the viewpoint of achieving both good conductivity and suppression of viscosity increase, 80 to 150 m ² / g is more preferable.
Further, from the viewpoint of developing the structure structure of carbon black and forming a conductive path, the amount of DBP (Dibutyl phthalate) oil absorbed is 100 to 500 ml / 100 g, which suppresses an increase in viscosity during preparation of an aqueous dispersion. From the viewpoint, it is preferably 100 to 300 ml / 100 g, and more preferably 150 to 250 ml / 100 g from the viewpoint of both forming the conductive path and suppressing the increase in viscosity.

In this application document, the carbon black N ₂ SA is defined as "Carbon black for rubber-Basic characteristics-Part 2, Specific surface area determination-Nitrogen adsorption method, Single point method" specified in JIS K 6217-2. The STSA of carbon black means the value measured according to JIS K 6217-7, "Carbon black for rubber-Basic properties-Part 7, Rubber compound-Multipoint method Nitrogen specific surface area (N _2)". It means the value measured according to "SA) and how to obtain the statistical thickness specific surface area (STSA)", and the DBP absorption amount of carbon black is defined in JIS K 6217-4 "Carbon black for rubber-basic characteristics-". It means a value measured according to "Part 4, How to Obtain DBP Absorption Amount".

Further, the average particle size of carbon black, which is a raw material of carbon oxide black, is preferably 20 to 100 nm from the viewpoint of increasing the number of particles per unit weight to obtain conductivity, and from the viewpoint of further improving the density. More preferably, it is 20 to 50 nm.
In this application document, the average particle size of carbon black means a numerical value measured by a method according to ASTM No. D3846.

Specific examples of carbon black include Talker Black # 5500, Talker Black # 4500, Talker Black # 4400, Talker Black # 3855, Talker Black # 3845, Talker Black # 3800 (all manufactured by Tokai Carbon Co., Ltd.), # 3030. , # 3050, # 3230, # 3400 (all manufactured by Mitsubishi Chemical Co., Ltd.), Conductex SC Ultra, Conductex K Ultra, Conductex 7097 Ultra, Conductex 7093, Conductex 7093, Conducex 7067 Ultra , Conductex 7054 Ultra, Conductex 7090, Conductex 7095 Ultra (all manufactured by Aditya Birla Group Columbian Chemicals Company), ENASCO® 150G, ENASCO® 210G, ENASCO® 250 ENASCO (registered trademark) 260G, ENASCO (registered trademark) 350G (hereinafter manufactured by Imerys Graphite & Carbon), VULCAN XC 72, LITX (registered trademark) 200, LITX (registered trademark) 300, LITX (registered trademark) 50 (manufactured by Cabot) ), Ketjen Black EC300J, Ketjen Black EC600JD (all manufactured by Lion Specialty Chemicals) and the like.

Examples of the method for preparing the carbon oxide black by introducing an anion exchange group into the carbon black include a method of oxidizing the carbon black with an oxidizing agent, a method of sulfonate, a method of reacting a diazonium salt, and the like. Anionic functional groups (acidic groups) can be introduced into the surface of carbon black by any of these methods.

The oxidation treatment with an oxidizing agent can be carried out by known methods such as a liquid phase method and a gas phase method. In the case of oxidation treatment by the liquid phase method, as an oxidizing agent, for example, peroxydisulfuric acid such as nitrate, sulfuric acid, chloric acid, peroxosulfuric acid, peroxoboric acid, peroxocarbonate, peroxophosphate, permanganic acid, peroxydisulfuric acid, etc. Examples of succinic acid, perchloric acid, hypochlorous acid, hydrogen peroxide, phosphonic acid, phosphoric acid, succinic acid, hypophosphoric acid, and salts of these acids can be mentioned. Examples thereof include alkali metal salts such as lithium, sodium and potassium, or ammonia salts.

In the liquid phase method, for example, carbon black having an anionic functional group (acidic group) on its surface can be obtained by putting carbon black into the dispersion liquid containing the oxidizing agent and stirring the mixture. The solvent for dispersing the oxidizing agent is preferably an aqueous medium, and examples of the aqueous medium include water and a water-soluble organic solvent, but water, particularly deionized water, is preferable from the viewpoint of economy and safety. Further, in order to uniformly disperse the carbon black particles, a surfactant may be added to the dispersion liquid containing the oxidizing agent, and any of anionic, nonionic and cationic surfactants is used as the surfactant. be able to.

The degree of liquid phase oxidation can be determined by adjusting the concentration of the oxidant in the dispersion containing the oxidant, the ratio of the amount of carbon black particles added to the aqueous solution of the oxidant, the oxidation treatment temperature, the treatment time, the stirring speed, and the like. Can be controlled.

In the liquid phase oxidation, for example, carbon black particles are added and mixed in an appropriate amount ratio in an aqueous solution of an oxidizing agent whose concentration has been adjusted, and an anionic functional group is introduced into the surface of the carbon black at room temperature to about 90 ° C. From the viewpoint of more efficiently introducing anionic functional groups onto the surface of carbon black, it can be preferably carried out by stirring for 1 to 20 hours under a temperature condition of 60 to 90 ° C. to form a slurry. In the liquid phase oxidation treatment, the carbon black particles may be wet-oxidized or dry-oxidized in advance, and by performing the wet-oxidation or dry-oxidation in advance, the carbon black particles can be efficiently dispersed in the aqueous solution of the oxidant. The liquid phase oxidation treatment can be performed uniformly and efficiently.

In addition, various methods for introducing an anionic functional group (acidic group) to the surface of carbon black by a method of reacting a diazonium salt are performed by a diazo coupling method on the surface of carbon black via a benzene ring on the surface of carbon black. Anion functional groups of, for example, -C ₆ H _4- COOH, -C ₆ H _4- SO ₃ H, -C ₆ H _4- PO ₄ ^2- H _2, etc. , For example, as described in Japanese Patent Publication No. 2000-512329.

The oxidation treatment by the vapor phase method can be carried out by exposing the carbon black particles to a gas atmosphere such as ozone, air, NOx, SOx, etc. According to the above vapor phase method, the drying cost is not required. There are advantages such as easier operation than the liquid phase method.

The aqueous slurry of carbon oxide black having one or more anionic functional groups on the surface obtained by the above oxidation treatment is a water-soluble chelating agent under the conditions of pH 2 to pH 4 after the carbon black is oxidized by the liquid phase method. Alternatively, it is preferably mixed with one or more selected from the salts thereof, and then the polyvalent metal ion is preliminarily separated using a separation membrane.

After producing carbon oxide black by the liquid phase method, if the reducing salt (salt such as polyvalent metal ion) in the slurry produced by the liquid phase oxidation is removed by preliminary separation, the neutralization reaction step described later will be smoothed. And it can be advanced efficiently. The reduced salt can be removed by using a separation membrane such as an ultrafiltration membrane (UF), a reverse osmosis membrane (RO), or an electrodialysis membrane. To the extent that the reduced salt is removed, for example, when the carbon black dispersion concentration is 20% by mass, it is desirable to purify the material so that the conductivity is less than 5 mS / cm. Insufficient separation and purification leads to a decrease in water dispersibility and dispersion stability, an increase in the viscosity of the dispersion, and is likely to cause equipment corrosion due to the dispersion.

In the treatment for removing the reduced salt, carbon black is oxidized by a liquid phase method, and then the conditions are preferably pH 2 to pH 4, more preferably pH 2.1 to pH 3.9, and further preferably pH 2.3 to pH 3.8. Below, it is preferable to mix the treatment liquid with one or more selected from the water-soluble chelating agent or a salt thereof. -COO surface of the carbon black ^- group, by forming one or more anionic functional group selected from ^{-SO 3-} group and _-PO ^{4 2-group} (acidic functional group), the pH of the liquid phase The range can be easily maintained and controlled. By controlling the pH within the above range, a complex of a polyvalent metal ion and a water-soluble chelating agent can be easily formed.

The water-soluble chelating agent is not particularly limited, but is preferably an aminocarboxylic acid or a salt thereof.

Examples of the aminocarboxylic acid or a salt thereof include ethylenediaminetetraacetic acid [EDTA], nitrilotriacetic acid, diethylenetriaminetetraacetic acid [DTPA], hydroxyethylethylenediaminetriacetic acid, and triethylenetetraminehexacetic acid [TTHA], 1,3-propanediamine. Tetraacetic acid, 1,3-diamino-2-hydroxypropanetetraacetic acid [CyDTA], hydroxyethyleneiminodiacetic acid, dihydroxyethylglycine, glycol etherdiaminetetraacetic acid, ethylenediaminediortohydroxyphenylacetic acid [EDDHA], ethylenediamine-N, N ′ -Bis [(2-hydroxy-5-methylphenyl) acetic acid] [EDDHMA], N, N ′-bis (2-hydroxybenzyl) ethylenediamine-N, N′-2 acetic acid [HBED], N, N ′- Bis (2-hydroxy-5-methylbenzyl) ethylenediamine-N, N'-2 acetic acid [HMBED], dicarboxymethylglutamic acid, ethylenediamine-N, N'-disuccinic acid, ethylenediaminetetrax (methylenephosphonic acid) [EDTPO], Nitrilotris (methylenephosphonic acid) [NTPO], propylenediaminetetra (methylenephosphonic acid) [PDTMP], 1-hydroxyethane-1,1-diphosphonic acid [HEDP], or one or more selected from salts thereof. it can. Ethylenediaminetetraacetic acid is preferable as the aminocarboxylic acid or a salt thereof, and specific examples of ethylenediaminetetraacetic acid include sodium ethylenediaminetetraacetate and potassium ethylenediaminetetraacetate.

The contact amount of the water-soluble chelating agent or its salt with respect to the carbon oxide black is 0.1 part by mass or more with respect to 100 parts by mass of the solid content of the carbon oxide black from the viewpoint of forming a complex of the polyvalent metal ion and the water-soluble chelating agent. From the viewpoint of more efficiently forming a complex, it is more preferably 0.5 parts by mass or more, and further preferably 1.0 part by mass or more. On the other hand, the contact amount of the water-soluble chelating agent or its salt with respect to the carbon oxide black is 15 parts by mass or less with respect to 100 parts by mass of the solid content of carbon oxide black because the complex is not formed when the addition amount is more than the necessary and sufficient amount. It is preferably 12.5 parts by mass or less, and further preferably 10 parts by mass or less from the viewpoint of economic efficiency.

When the dispersion obtained by oxidizing carbon black by the liquid phase method is brought into contact with the water-soluble chelating agent or a salt thereof, a method of mixing, stirring and mixing the water-soluble chelating agent or a salt thereof can be mentioned. Can be done.

When the above dispersion is brought into contact with a water-soluble chelating agent or a salt thereof, the contact temperature is preferably 40 ° C. or higher, more preferably 50 ° C., and more preferably 60 ° C. from the viewpoint of promoting complex formation. Is even more preferable. The contact time is preferably 30 minutes or more, more preferably 1 hour or more, and even more preferably 3 hours or more.

By mixing the dispersion and the water-soluble chelating agent or a salt thereof with pH 2 to 4, polyvalent metal ions soluble chelating agent is contained in the liquid phase, in particular ^{Fe 3 +, Al 3+, Cr} 3 + , etc. To form a polyvalent metal ion chelate complex by combining with the trivalent metal ion of the above, and since this polyvalent metal ion chelate complex can also be preliminarily separated during the treatment for removing the reduced salt, the polyvalent metal ion in the liquid phase The content of can be easily reduced.

Oxidized carbon black slurry obtained by the removal process (purification) of the reducing salt is formed on the carbon black surface, -COO ^- group, -SO ₃ ^- group, an acidic functional group such as _-PO ^{4 2-group,} The pH is maintained at 2 to 4 even after the purification treatment. Therefore, even if a chelate complex with a polyvalent metal ion centered on a trivalent metal ion remains in the slurry after the reduction salt removal treatment, the water-soluble chelating agent and the polyvalent metal ion remain. The chelate bond is maintained, and it is possible to suppress the capture of polyvalent metal ions on the carbon black surface in the subsequent neutralization step.

The carbon oxide black thus obtained is preferably a self-dispersing carbon black having an acidic group on the surface. A self-dispersing carbon black having an acidic group on its surface is one in which at least one hydrophilic group containing an acidic group is bonded directly to the surface of the carbon black or via another atomic group, and is suspended in water. It means that when it becomes turbid and becomes a dispersion liquid, a stable dispersed state can be maintained without adding a surfactant or a polymer compound, and the surface tension of the dispersion liquid shows a value almost equivalent to that of water. ..

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, the carbon oxide black is subjected to a neutralization step in the state of an aqueous slurry. Examples of the aqueous medium for dispersing the carbon oxide black include water and a water-soluble organic solvent, but water, particularly deionized water, is preferable from the viewpoint of economy and safety. The solid content concentration of carbon oxide black in the aqueous slurry is preferably 1.0 to 20.0% by mass, more preferably 1.0 to 15.0% by mass, and 1.0. It is more preferably ~ 10.0% by mass.

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, one selected from a water-soluble chelating agent or a salt thereof with respect to an aqueous slurry of carbon oxide black having one or more anionic functional groups on its surface. In the presence of the above, an alkali metal hydroxide is mixed and neutralized by heating, or an alkali metal hydroxide is mixed and neutralized by heating, and then one or more selected from a water-soluble chelating agent or a salt thereof is mixed. Perform the process.

Examples of the water-soluble chelating agent include one or more selected from those that can be used during the above-mentioned preliminary separation. Further, the contact amount of the water-soluble chelating agent or a salt thereof with respect to 100 parts by mass of the carbon oxide solid content is the same as the contact amount described above.

In the neutralization process
(I) An aqueous slurry of carbon oxide having one or more anionic functional groups on the surface is mixed with one or more selected from a water-soluble chelating agent or a salt thereof, and then mixed with an alkali metal hydroxide and heated. You can do Japanese processing
(Ii) An aqueous slurry of carbon oxide having one or more anionic functional groups on the surface is heat-neutralized by simultaneously mixing one or more selected from a water-soluble chelating agent or a salt thereof and an alkali metal hydroxide. You may
(Iii) One or more selected from water-soluble chelating agents or salts thereof after mixing alkali metal hydroxide with an aqueous slurry of carbon oxide black having one or more anionic functional groups on the surface and heat-neutralizing the mixture. May be mixed.

In the neutralization step, the mixing time of the aqueous slurry of carbon oxide having one or more anionic functional groups on the surface and one or more selected from the water-soluble chelating agent or a salt thereof is the above-mentioned (i) to (iii). The metal impurity component contained in the carbon oxide black is gradually eluted and replaced with the alkali metal by the heat neutralization treatment in the neutralization step.

Examples of the alkali metal hydroxide used in the neutralization step include one or more selected from sodium hydroxide, lithium hydroxide and potassium hydroxide.

The amount of alkali metal hydroxide used in the neutralization step can be appropriately determined according to the carbon oxide black to be neutralized, but the aqueous slurry of carbon oxide black is hydroxylated so as to have a pH of 6 to 12. It is preferable to mix the alkali metal, it is more preferable to mix the alkali metal hydroxide so as to have a pH of 7 to pH 12, and it is further preferable to mix the alkali metal hydroxide so as to have a pH of 8 to pH 12.

By mixing an alkali metal hydroxide so as to have a pH of 6 to 12 with an aqueous slurry of carbon oxide black and heat-neutralizing it, polyvalent metal ions captured on the surface of carbon oxide black, particularly divalent metal ions (especially divalent metal ions) Divalent iron ion, zinc ion, nickel ion, magnesium ion, calcium ion, etc.) are eluted and exchanged for alkali hydroxide, and the eluted polyvalent metal ion forms a polyvalent metal ion chelate complex with a water-soluble chelating agent. Since it becomes water-soluble and dissolves in the slurry, it can be easily removed by film separation.

The alkali metal hydroxide is preferably added in the form of an aqueous solution to the aqueous slurry of carbon oxide black having one or more anionic functional groups on the surface, and the aqueous medium for forming the aqueous solution is water or water. Although a acidic organic solvent can be mentioned, water, particularly deionized water, is preferable from the viewpoint of economy and safety.

In the neutralization step, alkali hydroxide is mixed with an aqueous slurry of carbon oxide black having one or more anionic functional groups on the surface and neutralized by heating. The heating temperature for heat neutralization is preferably 30 ° C. to 95 ° C., more preferably 60 ° C. to 95 ° C., and even more preferably 80 ° C. to 95 ° C.
Further, in the neutralization step, the time for mixing and holding the aqueous slurry of carbon oxide black having one or more anionic functional groups on the surface, the alkali hydroxide and the water-soluble chelating agent is preferably 30 minutes to 12 hours. 1-8 hours are more preferred, and 2-5 hours are even more preferred.

A polyvalent metal ion captured on the surface of carbon oxide black by mixing an aqueous slurry of carbon oxide black with an alkali metal hydroxide so as to have a pH of 6 to 12 and neutralizing at the above temperature and time. In particular, divalent metal ions (divalent iron ion, zinc ion, nickel ion, magnesium ion, calcium ion, etc.) are exchanged with alkali metal ions, and the polyvalent metal ions exchanged with these alkali metal ions are used as water-soluble chelating agents. In order to form a polyvalent metal ion chelate complex, it can be easily removed by a separation / removal step which is the next step.

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, after performing a neutralization step, a polyvalent metal ion chelate complex is separated from the mixed solution obtained in the neutralization step using a separation membrane. Perform a separation / removal step to remove.

The separation membrane used in the separation / removal step is not particularly limited, but is preferably an ultrafiltration membrane (UF), a reverse osmosis membrane (RO), or an electrodialysis membrane. With the separation membrane, the polyvalent metal ions trapped on the surface of carbon oxide black can be separated and removed as a polyvalent metal ion chelate complex, and at the same time, the residual salt due to excess alkali hydroxide can be removed from the system. At the same time, it is also effective in suppressing the reaggregation of carbon oxide black particles.

The separation treatment in the separation / removal step may be performed to such an extent that the polyvalent metal ion chelate complex and the residual salt due to the excess alkali hydroxide can be sufficiently removed from the system. For example, the content concentration of the carbon oxide black particles is 20. In the case of mass%, it is preferable to carry out until the conductivity of the aqueous dispersion becomes 5 mS / cm or less, and more preferably to carry out until it becomes 2 mS / cm or less.

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, the preferred ranges of the acidic hydroxyl group amount, the carboxyl group equivalent amount and the hydroxyl group amount of the obtained aqueous dispersion are described above. It is the same as the preferable range of the amount of acidic hydroxyl group, the amount of carboxyl group equivalent and the amount of hydroxyl group of carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material of the present invention.

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, the amount of -SO ₃ H groups and the amount of -PO ₄ H ₂ groups of carbon oxide in the obtained aqueous dispersion are not particularly limited. The measuring method thereof is the same as that described in the above description of the carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material of the present invention.

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, the preferred ranges of the nitrogen adsorption specific surface area N ₂ SA, DBP oil absorption amount and average particle size of the obtained carbon oxide black are also described above. The nitrogen adsorption specific surface area N ₂ SA, DBP oil absorption amount and average particle size of carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material of the present invention are the same as the preferable ranges.

In the method for producing an aqueous dispersion of a conductive carbon black raw material according to the present invention, the preferred ranges of the polyvalent metal content concentration and the compressive resistivity in the obtained heat-treated product of carbon oxide are also described above. A suitable range of polyvalent metal content of carbon oxide black contained in the aqueous dispersion of the conductive carbon black raw material of the present invention and carbon oxide contained in the aqueous dispersion of the conductive carbon black raw material of the present invention described above. This is similar to the preferred range of compressive resistivity after heat treatment of black.

The acidic carbon black in the aqueous dispersion obtained by the production method according to the present invention serves as a raw material for the conductive carbon black, and the desired properties are obtained by separately removing the anionic functional group (acidic functional group) on the surface of the acidic carbon black. It is possible to obtain a conductive carbon black having.

According to the present invention, there is provided a method for producing an aqueous dispersion of a conductive carbon black raw material, which can easily and inexpensively produce a conductive material capable of exhibiting excellent conductivity by reducing the content ratio of polyvalent metal ions. Can be done.

<Conductive carbon black powder>
Next, the conductive carbon black powder according to the present invention will be described.
The conductive carbon black powder according to the present invention
Nitrogen adsorption specific surface area N ₂ SA is 100-1500 m ² / g,
The value obtained by subtracting the statistical thickness specific surface area STSA from the nitrogen adsorption specific surface area N ₂ SA is 50 to 200 m ² / g.
DBP oil absorption is 100-500ml / 100g,
The average particle size is 20-100 nm
Polyvalent metal content concentration is 10 to 100 mass ppm,
Compressed electrical resistivity is 0.05 to 0.23 Ω ・ cm
It is characterized by being.

The conductive carbon black powder according to the present invention has a nitrogen adsorption specific surface area N ₂ SA of 100 to 1500 m ² / g from the viewpoint of obtaining conductivity by increasing the number of particles per unit weight. From the viewpoint of suppressing the increase in viscosity during the preparation of the aqueous dispersion, the content is preferably 100 to 500 m ² / g, and from the viewpoint of achieving both the good conductivity and the suppression of the increase in viscosity, the content is 200 to 300 m ² / g. More preferred.

In the conductive carbon black powder according to the present invention, when the nitrogen adsorption specific surface area N ₂ SA is within the above range, the number of particles per unit weight can be easily increased and the conductivity can be easily improved. ..

For the nitrogen adsorption specific surface area N ₂ SA of the conductive carbon black powder, a fully automatic surface area measuring device (Gemini 2375 manufactured by Shimadzu Corporation) was used, and "carbon black for rubber" specified in JIS K 6217-2 was used. -Basic characteristics-Part 2, How to find the specific surface area-Nitrogen adsorption method, single point method "means the value measured.

The conductive carbon black powder according to the present invention has a nitrogen adsorption specific surface area N ₂ SA and a statistical thickness ratio from the viewpoint of increasing the number of particles per unit weight to obtain conductivity by having pores on the surface. surface area is intended minus (STSA) is 50 to 200 m ² / g, preferably has a 50 to 150 m ² / g from the viewpoint of suppressing increase in viscosity during aqueous dispersion preparation, the excellent conductivity From the viewpoint of achieving both properties and suppression of viscosity increase, 80 to 150 m ² / g is more preferable.

The statistical specific surface area of the conductive carbon black powder was determined by using a fully automatic surface area measuring device (Gemini 2375 manufactured by Shimadzu Corporation) and defined in JIS K 6217-7 "Carbon black for rubber-". It means the value measured according to "Basic Properties-Part 7, Rubber Formulation-Multipoint Method Nitrogen Specific Surface Area (N ₂ SA) and Statistical Thickness Specific Surface Area (STSA)".

The conductive carbon black powder according to the present invention has a DBP (Dibutyl phthalate) oil absorption of 100 to 500 ml / 100 g from the viewpoint of developing a structural structure of carbon black and forming a conductive path, and is aqueous. From the viewpoint of suppressing the increase in viscosity at the time of preparing the dispersion, 100 to 300 ml / 100 g is preferable, and from the viewpoint of both forming the conductive path and suppressing the increase in viscosity, 150 to 250 ml / 100 g is more preferable.

When the DBP oil absorption amount of the conductive carbon black powder according to the present invention is within the above range, a conductive path is easily formed and the conductivity can be easily improved.

The DBP oil absorption amount of the conductive carbon black powder means a value measured according to "Carbon Black for Rubber-Basic Characteristics-Part 4, How to Obtain DBP Absorption Amount" specified in JIS K 6217-4. ..

The conductive carbon black powder according to the present invention has an average particle diameter of 20 to 100 nm from the viewpoint of increasing the number of particles per unit weight to obtain conductivity, and from the viewpoint of further improving the density. Those having a diameter of 20 to 80 nm are preferable, and those having a diameter of 20 to 50 nm are more preferable.

When the average particle size of the conductive carbon black powder according to the present invention is within the above range, the number of particles per unit weight can be easily increased and the conductivity can be easily improved.

The average particle size of the conductive carbon black powder means a value measured by a method according to ASTM No. D3846.

The conductive carbon black powder according to the present invention has a polyvalent metal content of 10 to 100 mass ppm from the viewpoint of suppressing metal elution into the system when used in the present application. It is preferably ~ 80 mass ppm, and more preferably 10 to 50 mass ppm.

When the polyvalent metal content of the conductive carbon black powder according to the present invention is within the above range, deterioration of battery performance can be easily suppressed when used as a positive electrode material for a lithium secondary battery.

The polyvalent metal content concentration of the conductive carbon black powder means a value measured by a method conforming to JIS K 0133. The content of each metal component is measured using an inductively coupled plasma emission spectroscopic analyzer (ICPS-7510, manufactured by Shimadzu Corporation). As the metal component, Mg, Al, Ca, Cr, Mn, Fe, Ni, Cu, Zn, and Pb are measured.

The conductive carbon black powder according to the present invention has a compressive electrical resistivity of 0.05 to 0.23 Ω · cm from the viewpoint of functioning as a conductive material in a positive electrode material, and is conductive even when a small amount is added. From the viewpoint of obtaining properties, those having a thickness of 0.05 to 0.20 Ω · cm are preferable, and those having a thickness of 0.05 to 0.10 Ω · cm are more preferable.

Since the compressive electrical resistivity of the conductive carbon black powder according to the present invention is within the above range, deterioration of battery performance can be easily suppressed when used as a positive electrode material for a lithium secondary battery.

The compressive electrical resistivity of the conductive carbon black powder means a value measured by a method based on JIS K 1469-2003. A load cell Ezgraph manufactured by Shimadzu Corporation was used as an apparatus.

The amount of acidic hydroxyl groups of the conductive carbon black powder according to the present invention is preferably 50 μmol / g to 300 μmol / g, preferably 50 μmol / g to 250 μmol / g, from the viewpoint of removing anionic groups on the surface. Is more preferable, and 50 μmol / g to 200 μmol / g is even more preferable. The amount of acidic hydroxyl groups of carbon oxide black contained in the conductive carbon black powder according to the present invention means the sum of the amount of carboxyl groups (−COO ⁻ ) and the amount of hydroxyl groups (−O ⁻ ) of carbon oxide black.

The amount of acidic hydroxyl groups in the conductive carbon black powder means a value obtained by the following measuring method.
(Sample preparation: acid cleaning and standard solution addition)
1.0 g of conductive carbon black powder is collected in a centrifuge tube, 5.0 g of 0.5 mol / l hydrochloric acid is added, and the mixture is shaken several times and then solid-liquid separated by a centrifuge. After performing this operation a total of 4 times, the solid matter is transferred to a 100 ml beaker and dried at 110 ° C. The dried solid is crushed in a mortar, 1.0 g of the obtained carbon black powder is collected in an Erlenmeyer flask, 25 ml of 0.1 mol / l NaOH is added to the Erlenmeyer flask, and then the triangle is used with a shaker. Shake the flask for 4 hours. Transfer the shaken liquid to a centrifuge tube and collect the supernatant liquid as a measurement sample.
(Measurement procedure: titration method and acid value calculation method)
The acid value is measured by potentiometric titration using an automatic titration device (809Titrando, manufactured by Metrohm). Prior to the measurement of the sample obtained above, 25 ml of 0.1 mol / l NaOH was titrated with 0.1 mol / l HCl as a blank, and the amount of HCl required for neutralization was measured. Titration was performed with 1 mol / l HCl, and the amount of HCl required for neutralization was measured. The obtained measured value was substituted into the following formula to determine the acid value. The meanings of the symbols in the formula are shown below.
V _Blank [ml]: Titration amount of 0.1 mol / l NaOH required for neutralization when 25 ml of NaOH was titrated with 0.1 mol / l HCl V _Sample [ml]: Titration of 25 ml of sample with 0.1 mol / l HCl Titration amount required for neutralization N _HCl [mol / l]: Concentration of HCl standard solution M _sample [g]: Conductive carbon black weight in measurement sample Acid value [mmol / g] = (V _Blank −V _Sample ) × N _HCl / M _sample

For -SO ₃ H group content and _-PO 4 _{H 2} groups of conductive carbon black powder according to the present invention is not particularly limited.

The conductive carbon black powder according to the present invention can be suitably prepared by the method for producing the conductive carbon black powder according to the present invention described below.

According to the present invention, it is possible to provide a conductive carbon black powder that is useful as a conductive material and can be easily manufactured at low cost and can exhibit excellent conductivity by reducing the content ratio of polyvalent metal ions. ..

<Manufacturing method of conductive carbon black powder>
Next, a method for producing the conductive carbon black powder according to the present invention will be described.

The method for producing a conductive carbon black powder according to the present invention (hereinafter, referred to as the powder production method 1 according to the present invention) is characterized by heat-treating an aqueous dispersion of a conductive carbon black raw material according to the present invention. Is to be.

The details of the aqueous dispersion of the conductive carbon black raw material according to the present invention are as described above.

When the aqueous dispersion of the conductive carbon black raw material according to the present invention is heat-treated in order to obtain the conductive carbon black powder according to the present invention, the heat treatment condition is carbon oxide black which is a conductive carbon black raw material. The condition is not particularly limited as long as the anion functional group (acidic functional group) can be sufficiently removed.
As the heat treatment conditions, the heat treatment is preferably performed at 500 ° C. to 600 ° C. in an inert atmosphere, and more preferably 500 ° C. to 550 ° C. from the viewpoint of shortening the temperature rising time.
The heat treatment time is preferably 30 to 600 minutes, more preferably 30 to 180 minutes, and even more preferably 60 to 120 minutes.
The gas type used for the inert atmosphere is not particularly limited, and one or more selected from the inert gas such as nitrogen gas, argon gas, and helium gas can be used.
By the above heat treatment, anionic functional groups (acidic functional groups) on the surface of acidic carbon black, which is a raw material for conductive carbon black, are preferably removed, and conductive carbon black powder having desired characteristics can be obtained.

The method for producing the conductive carbon black powder according to the present invention (hereinafter referred to as the powder production method 2 according to the present invention) has a nitrogen adsorption specific surface area N ₂ SA of 100 to 1500 m ² / g and a nitrogen adsorption specific surface area N. _The value obtained by subtracting the statistical thickness specific surface area STSA from ₂ SA is 50 to 200 m ² / g, the DBP oil absorption is 100 to 500 ml / 100 g, the average particle size is 100 to 500 nm, and one or more anions are formed on the surface. For an aqueous slurry of carbon oxide black having a functional group
The alkali metal hydroxide is mixed and neutralized by heating in the presence of one or more selected from the water-soluble chelating agent or a salt thereof, or the alkali metal hydroxide is mixed and neutralized by heating and then the water-soluble chelating agent or its A neutralization process that mixes one or more selected from salts,
An aqueous dispersion of a conductive carbon black raw material is prepared by performing a separation / removal step of separating and removing a polyvalent metal ion chelate complex from the mixed solution obtained in the neutralization step using a separation membrane, and then
The present invention is characterized in that the obtained aqueous dispersion of the conductive carbon black raw material is heat-treated to perform a functional group removing step of removing the anionic functional group of the carbon oxide black.

In the powder manufacturing method 2 according to the present invention, the contents up to the preparation of an aqueous dispersion of a conductive carbon black raw material by subjecting an aqueous slurry of carbon oxide black to a neutralization step and a separation / removal step are described in the present invention. Since it is common to the method for producing an aqueous dispersion of the conductive carbon black raw material, the details are the same as those described above.

In the powder production method 2 according to the present invention, the aqueous dispersion of the conductive carbon black raw material obtained by subjecting the aqueous slurry of carbon oxide black to a neutralization step and a separation / removal step is heat-treated to oxidize the above. A functional group removing step of removing anionic functional groups of carbon black is performed.

In the powder production method 2 according to the present invention, the heat treatment conditions in the functional group removing step are conditions under which the anionic functional groups (acidic functional groups) of carbon oxide black, which is a raw material for conductive carbon black, can be sufficiently removed. If there is, there is no particular limitation.
As the heat treatment conditions, the heat treatment is preferably performed at 500 ° C. to 600 ° C. in an inert atmosphere, and more preferably 500 ° C. to 550 ° C. from the viewpoint of shortening the temperature rising time.
The heat treatment time is preferably 30 to 600 minutes, more preferably 30 to 180 minutes, and even more preferably 60 to 120 minutes.
The gas type used for the inert atmosphere is not particularly limited, and one or more selected from the inert gas such as nitrogen gas, argon gas, and helium gas can be used.
By the above heat treatment, the anionic functional group (acidic functional group) on the surface of the acidic carbon black which is the raw material of the conductive carbon black is preferably removed, and the conductive carbon black powder having desired characteristics can be obtained.

According to the present invention, a conductive carbon black powder capable of easily and inexpensively producing a conductive carbon black powder useful as a conductive material capable of exhibiting excellent conductivity by reducing the content ratio of polyvalent metal ions. A manufacturing method can be provided.

<Manufacturing method of positive electrode material for lithium ion secondary battery>
Next, a method for producing a positive electrode material for a lithium ion secondary battery according to the present invention will be described.

The method for producing a positive electrode material for a lithium ion secondary battery according to the present invention is an aqueous dispersion of a conductive carbon black raw material according to the present invention, or an aqueous dispersion of a conductive carbon black raw material obtained by the production method according to the present invention. , The conductive carbon black powder according to the present invention or the conductive carbon black powder obtained by the method according to the present invention.
Mix at least with electrode active material and binder,
It is characterized by being applied to an electrode substrate and dried.

In the method for producing a positive electrode material for a lithium ion secondary battery according to the present invention, the aqueous dispersion of the conductive carbon black raw material according to the present invention and the aqueous dispersion of the conductive carbon black raw material obtained by the production method according to the present invention. The details of the conductive carbon black powder according to the present invention or the conductive carbon black powder obtained by the method according to the present invention are as described above.

According to the present invention, a positive electrode for a lithium ion secondary battery using conductive carbon black powder as a conductive material, which can exhibit excellent conductivity by reducing the content ratio of polyvalent metal ions and can be easily produced at low cost. A method for producing a material can be provided.

(Example)
The contents of the present invention will be described below with specific examples and comparative examples. However, the present invention is not limited to these examples. In the following Examples and Comparative Examples, the pH was determined by the method specified in JIS Z 8802.

(Example 1)
<Preparation of carbon oxide black-containing slurry>
Carbon black (Furness carbon black, manufactured by Tokai Carbon Co., Ltd., TB # 5500, nitrogen adsorption specific surface area N ₂ SA is 225 m ² / g, nitrogen adsorption specific surface area N ₂ SA minus statistical thickness specific surface area (STSA) 150 g (90 m ² / g, DBP oil absorption amount 155 ml / 100 g, average particle size 200 nm) was added to 3000 ml of a 2.0 N sodium persulfate aqueous solution using deionized water, the reaction temperature was 90 ° C., and the stirring speed was increased. The surface of the carbon black was liquid phase oxidized by treating at 300 rpm for 3 hours.
Next, the reduced salt in the obtained slurry was washed with an ultrafiltration membrane (manufactured by Asahi Kasei Corporation, AHP-1010, molecular weight cut off of 50,000) with water until the conductivity was less than 3 mS / cm, and desalted and purified. .. The pH of the obtained slurry containing carbon oxide black was pH 3.
Sodium ethylenediamine tetraacetate was added to the above-mentioned slurry containing carbon oxide black washed with water (carbon oxide black solid content concentration 5% by mass) per carbon oxide black solid content (relative to carbon oxide black solid content 100% by mass). 5% by mass was added, and the reaction was carried out at a reaction temperature of 25 ° C. and a stirring speed of 300 rpm for 15 minutes.
The carbon black slurry obtained by reacting with the above sodium ethylenediamine tetraacetate was washed with an ultrafiltration membrane (AHP-1010 manufactured by Asahi Kasei Co., Ltd., specific surface area 50,000) with water until the conductivity was less than 3 mS / cm. Preliminarily separated polyvalent metal ions by desalting and purification, the nitrogen adsorption specific surface area N ₂ SA is 225 m ² / g, and the value obtained by subtracting the statistical thickness specific surface area (STSA) from the nitrogen adsorption specific surface area N ₂ SA. 90 m ² / g, DBP oil absorption is 155 ml / 100 g, average particle size is 200 nm, and the amount of acidic hydroxyl groups is 900 μmol / g. Contains carbon oxide black having an anionic functional group on the surface. A slurry was obtained.

<Neutralization treatment>
In the carbon oxide-containing slurry obtained by pre-separating the polyvalent metal ions obtained in the above <Preparation of carbon oxide-containing slurry>, sodium ethylenediamine tetraacetate was added per carbon oxide black solid content (carbon oxide black solid content). 5% by mass was added (with respect to 100% by mass), and an aqueous sodium hydroxide solution was added so that the pH of the slurry became 11, and a neutralization reaction was carried out at a reaction temperature of 95 ° C. and a stirring speed of 300 rpm for 3 hours.

<Separation and removal processing>
A chelate complex with a salt remaining on the mixed solution obtained by performing the neutralization reaction in the above <neutralization treatment> using an ultrafiltration membrane (AHP-1010 manufactured by Asahi Kasei Co., Ltd., specific surface area 50,000). Is washed with water and concentrated, and the value obtained by subtracting the statistical thickness specific surface area (STSA) from the nitrogen adsorption specific surface area N ₂ SA is 225 m ² / g and the nitrogen adsorption specific surface area N ₂ SA is 90 m ² / g. , DBP oil absorption amount is 155 ml / 100 g, average particle size is 200 nm, acidic hydroxyl group amount is 900 μmol / g, and a conductive carbon black raw material containing 20% by mass of carbon oxide black having an anionic functional group on the surface. Water dispersion was prepared.

<Functional group removal treatment>
Next, the aqueous dispersion of the conductive carbon black raw material obtained in the <separation / removal treatment> was heat-treated at 110 ° C. for 720 minutes in a dryer to remove water, and then the dried product obtained in the graphite pit. Conductive carbon black powder (nitrogen adsorption specific surface area N ₂ SA225 m ² / g) from which anionic functional groups on the surface of carbon black have been removed by heat treatment at 500 ° C. for 1 hour in an N ₂ gas atmosphere. , Nitrogen adsorption specific surface area N ₂ SA minus statistical thickness specific surface area (STSA) is 90 m ² / g, DBP oil absorption is 155 ml / 100 g, average particle size is 25 nm, acidic hydroxyl group amount is 100 μmol / g). Prepared.

(Comparative Example 1)
The concentration of carbon oxide was the same as in Example 1 except that neither sodium ethylenediamine tetraacetate was added in the <preparation of the carbon black oxide-containing slurry> and the <neutralization treatment> of Example 1. After preparing an aqueous dispersion of a conductive carbon black raw material having a weight of 20% by mass, a functional group removal treatment was carried out in the same manner as in Example 1, and the nitrogen adsorption specific surface area N ₂ SA225 m ² / g, the nitrogen adsorption specific surface area N. ₂ SA minus the statistical specific surface area (STSA) is 90 m ² / g, DBP oil absorption is 155 ml / 100 g, average particle size is 200 nm, and the amount of acidic hydroxyl groups is 100 μmol / g. A carbon black powder was prepared.

(Comparative Example 2)
Nitrogen adsorption specific surface area N ₂ SA225 m ² / g, nitrogen adsorption ratio in the same manner as in Example 1 except that the <functional group removal treatment> of Example 1 was not heat-treated at 500 ° C. in an inert atmosphere. The value obtained by subtracting the statistical specific surface area (STSA) from the surface area N ₂ SA is 90 m ² / g, the DBP oil absorption is 155 ml / 100 g, the average particle size is 200 nm, and the amount of acidic hydroxyl groups is 900 μmol / g. A conductive carbon black powder was prepared.

<Measurement method of metal component content>
In Example 1 and Comparative Examples 1 and 2, the aqueous dispersion of each conductive carbon black raw material obtained after the <separation / removal treatment> was diluted with a nitric acid solution, and then an inductively coupled plasma emission spectroscopic analyzer ((( The content of each polyvalent metal component was measured by ICPS-7510) manufactured by Shimadzu Corporation.
For comparison, the content of the multivalent metal component in carbon black (TB # 5500) used as a raw material was also measured in the same manner.

The results obtained are shown in Table 1.
The numerical value in the table is the total amount (mass ppm) of the multivalent metal contained in carbon black. As the polyvalent metal, Mg, Al, Ca, Cr, Mn, Fe, Ni, Cu, Zn, and Pb were measured.

<Measurement method of compressed electrical resistance of carbon black powder>
The compressive electrical resistance of the conductive carbon black powders obtained in Example 1 and Comparative Examples 1 and 2 was measured by a method according to JIS K 1469-2003.
For comparison, the compressed electrical resistance of carbon black (TB # 5500) used as a raw material was also measured in the same manner.
The results are shown in Table 1.

From Table 1, although the conductive carbon black powder obtained in Example 1 was derived from furnace black, it was complex-formed with a water-soluble chelating agent and then the polyvalent metal was separated and removed. Therefore, compared to carbon black used as a raw material, the polyvalent metal concentration is significantly reduced to about 2.0% ((49/2000) × 100), and the compressive electrical resistivity is 0. Since it can exhibit excellent conductivity as low as .20 Ω · cm, it can be seen that it is suitable as a material for forming a positive electrode material for a lithium ion secondary battery.
On the other hand, from Table 1, the polyvalent metal was not sufficiently removed in Comparative Example 1, and the anionic functional group (acidic functional group) was not sufficiently removed in Comparative Example 2. Since the compressed electrical specific resistance is high, it can be seen that none of them is suitable as a material for forming a positive electrode material for a lithium ion secondary battery.

According to the present invention, an aqueous dispersion of a conductive carbon black raw material capable of easily and inexpensively producing a conductive material capable of exhibiting excellent conductivity with a reduced content ratio of polyvalent metal ions, such a conductive carbon black raw material A method for producing an aqueous dispersion, a method for producing a conductive carbon black powder, a method for producing a conductive carbon black powder, and a method for producing a positive electrode material for a lithium ion secondary battery can be provided.

Claims (11)

Nitrogen adsorption specific surface area N ₂ SA is 100-1500 m ² / g,
The value obtained by subtracting the statistical thickness specific surface area STSA from the nitrogen adsorption specific surface area N ₂ SA is 50 to 200 m ² / g.
DBP oil absorption is 100-500ml / 100g,
The average particle size is 100-500 nm
The polyvalent metal content is 10 to 100 mass ppm,
An aqueous dispersion of a conductive carbon black raw material, which contains carbon oxide black having a compressed electrical resistivity of 0.05 to 0.23 Ω · cm after heat treatment. Nitrogen adsorption specific surface area N ₂ SA is 100 to 1500 m ² / g, nitrogen adsorption specific surface area N ₂ SA minus statistical thickness specific surface area STSA is 50 to 200 m ² / g, DBP oil absorption is 100 to 500 ml / g. For an aqueous slurry of carbon oxide having 100 g, an average particle size of 100 to 500 nm, and one or more anionic functional groups on the surface.
The alkali metal hydroxide is mixed and neutralized by heating in the presence of one or more selected from the water-soluble chelating agent or a salt thereof, or the alkali metal hydroxide is mixed and neutralized by heating and then the water-soluble chelating agent or its A neutralization process that mixes one or more selected from salts,
A method for producing an aqueous dispersion of a conductive carbon black raw material, which comprises performing a separation / removal step of separating and removing a polyvalent metal ion chelate complex from the mixed solution obtained in the neutralization step using a separation membrane. The method for producing an aqueous dispersion of a conductive carbon black raw material according to claim 2, wherein in the neutralization step, the alkali metal hydroxide is mixed with the aqueous slurry of carbon oxide black so as to have a pH of 6 to 12. The method for producing an aqueous dispersion of a conductive carbon black raw material according to claim 2 or 3, wherein the water-soluble chelating agent is an aminocarboxylic acid or a salt thereof. Carbon black oxide having one or more anionic functional groups on the surface is mixed with one or more selected from water-soluble chelating agents or salts thereof under the conditions of pH 2 to pH 4 after oxidizing the carbon black by a liquid phase method. The method for producing an aqueous dispersion of a conductive carbon black raw material according to any one of claims 2 to 4, wherein the polyvalent metal ions are preliminarily separated using a separation membrane. The method for producing an aqueous dispersion of a conductive carbon black raw material according to any one of claims 2 to 5, wherein the separation membrane is an ultrafiltration membrane (UF), a reverse osmosis membrane (RO), or an electrodialysis membrane. Nitrogen adsorption specific surface area N ₂ SA is 100-1500 m ² / g,
The value obtained by subtracting the statistical thickness specific surface area STSA from the nitrogen adsorption specific surface area N ₂ SA is 50 to 200 m ² / g.
DBP oil absorption is 100-500ml / 100g,
The average particle size is 20-100 nm
Polyvalent metal content concentration is 10 to 100 mass ppm,
Compressed electrical resistivity is 0.05 to 0.23 Ω ・ cm
A conductive carbon black powder characterized by being. A method for producing a conductive carbon black powder, which comprises heat-treating the aqueous dispersion of the conductive carbon black raw material according to claim 1. Nitrogen adsorption specific surface area N ₂ SA is 100 to 1500 m ² / g, nitrogen adsorption specific surface area N ₂ SA minus statistical thickness specific surface area STSA is 50 to 200 m ² / g, DBP oil absorption is 100 to 500 ml / g. For an aqueous slurry of carbon oxide having 100 g, an average particle size of 100 to 500 nm, and one or more anionic functional groups on the surface.
The alkali metal hydroxide is mixed and neutralized by heating in the presence of one or more selected from the water-soluble chelating agent or a salt thereof, or the alkali metal hydroxide is mixed and neutralized by heating and then the water-soluble chelating agent or its A neutralization process that mixes one or more selected from salts,
An aqueous dispersion of a conductive carbon black raw material is prepared by performing a separation / removal step of separating and removing a polyvalent metal ion chelate complex from the mixed solution obtained in the neutralization step using a separation membrane, and then
A method for producing a conductive carbon black powder, which comprises performing a functional group removing step of heat-treating the obtained aqueous dispersion of the conductive carbon black raw material to remove the anionic functional group of the carbon oxide black. The method for producing a conductive carbon black powder according to claim 8 or 9, wherein the heat treatment of the aqueous dispersion of the conductive carbon black raw material is performed at 500 to 600 ° C. The aqueous dispersion of the conductive carbon black raw material according to claim 1, the aqueous dispersion of the conductive carbon black raw material obtained by the production method according to any one of claims 2 to 6, according to claim 7. The conductive carbon black powder or the conductive carbon black powder obtained by the production method according to any one of claims 8 to 10.
Mix at least with electrode active material and binder,
A method for producing a positive electrode material for a lithium ion secondary battery, which comprises applying and drying to an electrode substrate.